Why examples first
The microformats The microformats process requirement to first document Best Practices for Examples Pages of real world publishing behavior is an adaptation of the "gather information" step in the scientific method to standards development. The microformats process is the first to explicitly adopt and require this methodology among standards efforts, and to date is the only effort to do so in the world of standards development as compared to other standards development organizations.
Common behavior in typical standards development organizations is to simply invent standards / formats based upon intuition or so-called "expertise", and to either not bother collecting examples at all, or to do so only incidentally, or for brief illustration, always serving at best as secondary. Sometimes this intuition masquerades as formal "requirements" that are similarly invented rather than based upon actual publishing practice in the real world.
That non-scientific technique has been tried in many (most) standards and results more often than not in bloated overly complex (certainly not "micro") standards. There are exceptions, where an individual with exceptional discipline and near obsession with simplicity makes something small and elegant, but they are the exception, not the rule, and even in those cases you will often find features that no one ever ends up using.
This particular contrast between traditional standards development and microformats can also be summarized as the philosohpical difference between a priori and a posteriori knowledge. That is, traditional standards take more of an a priori approach, independent of real-world experience (data), while microformats take an a posteriori approach that is dependent on real-world experience, where "experience" in this sentence refers to actual "experiences" that occur in the real-world, in particular the Web, and are documented as such, not someone being "experienced" or an expert in their field etc.